﻿/*
  This file is part of Sanmill.
  Copyright (C) 2019-2021 The Sanmill developers (see AUTHORS file)

  Sanmill is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  Sanmill is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef _WIN32
#if _WIN32_WINNT < 0x0601
#undef  _WIN32_WINNT
#define _WIN32_WINNT 0x0601 // Force to include needed API prototypes
#endif

#ifndef NOMINMAX
#define NOMINMAX
#endif

#include <windows.h>
// The needed Windows API for processor groups could be missed from old Windows
// versions, so instead of calling them directly (forcing the linker to resolve
// the calls at compile time), try to load them at runtime. To do this we need
// first to define the corresponding function pointers.
extern "C" {
    typedef bool(*fun1_t)(LOGICAL_PROCESSOR_RELATIONSHIP,
                          PSYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX, PDWORD);
    typedef bool(*fun2_t)(USHORT, PGROUP_AFFINITY);
    typedef bool(*fun3_t)(HANDLE, CONST GROUP_AFFINITY *, PGROUP_AFFINITY);
}
#endif

#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <vector>
#include <cstdlib>

#if defined(__linux__) && !defined(__ANDROID__)
#include <stdlib.h>
#include <sys/mman.h>
#endif

#if defined(__APPLE__) || defined(__ANDROID__) || defined(__OpenBSD__) || (defined(__GLIBCXX__) && !defined(_GLIBCXX_HAVE_ALIGNED_ALLOC) && !defined(_WIN32))
#define POSIXALIGNEDALLOC
#include <stdlib.h>
#endif

#include "misc.h"
#include "thread.h"

using namespace std;

namespace
{

/// Version number. If Version is left empty, then compile date in the format
/// DD-MM-YY and show in engine_info.
const string Version = "";

/// Our fancy logging facility. The trick here is to replace cin.rdbuf() and
/// cout.rdbuf() with two Tie objects that tie cin and cout to a file stream. We
/// can toggle the logging of std::cout and std:cin at runtime whilst preserving
/// usual I/O functionality, all without changing a single line of code!
/// Idea from http://groups.google.com/group/comp.lang.c++/msg/1d941c0f26ea0d81

struct Tie : public streambuf
{
    // MSVC requires split streambuf for cin and cout

    Tie(streambuf *b, streambuf *l) : buf(b), logBuf(l)
    {
    }

    int sync() override
    {
        return logBuf->pubsync(), buf->pubsync();
    }

    int overflow(int c) override
    {
        return log(buf->sputc((char)c), "<< ");
    }

    int underflow() override
    {
        return buf->sgetc();
    }

    int uflow() override
    {
        return log(buf->sbumpc(), ">> ");
    }

    streambuf *buf, *logBuf;

    int log(int c, const char *prefix)
    {
        static int last = '\n'; // Single log file

        if (last == '\n')
            logBuf->sputn(prefix, 3);

        return last = logBuf->sputc((char)c);
    }
};

class Logger
{
    Logger() : in(cin.rdbuf(), file.rdbuf()), out(cout.rdbuf(), file.rdbuf())
    {
    }

    ~Logger()
    {
        start("");
    }

    ofstream file;
    Tie in, out;

public:
    static void start(const std::string &fname)
    {
        static Logger l;

        if (!fname.empty() && !l.file.is_open()) {
            l.file.open(fname, ifstream::out);

            if (!l.file.is_open()) {
                cerr << "Unable to open debug log file " << fname << endl;
                exit(EXIT_FAILURE);
            }

            cin.rdbuf(&l.in);
            cout.rdbuf(&l.out);
        } else if (fname.empty() && l.file.is_open()) {
            cout.rdbuf(l.out.buf);
            cin.rdbuf(l.in.buf);
            l.file.close();
        }
    }
};

} // namespace


/// engine_info() returns the full name of the current Sanmill version. This
/// will be either "Sanmill <Tag> DD-MM-YY" (where DD-MM-YY is the date when
/// the program was compiled) or "Sanmill <Version>", depending on whether
/// Version is empty.

const string engine_info(bool to_uci)
{
    const string months("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec");
    string month, day, year;
    stringstream ss, date(__DATE__); // From compiler, format is "Sep 21 2008"

    ss << "Sanmill " << Version << setfill('0');

    if (Version.empty()) {
        date >> month >> day >> year;
        ss << setw(2) << day << setw(2) << (1 + months.find(month) / 4) << year.substr(2);
    }

    ss << (to_uci ? "\nid author " : " by ")
       << "the Sanmill developers (see AUTHORS file)";

    return ss.str();
}


/// compiler_info() returns a string trying to describe the compiler we use

const std::string compiler_info()
{
#define stringify2(x) #x
#define stringify(x) stringify2(x)
#define make_version_string(major, minor, patch) stringify(major) "." stringify(minor) "." stringify(patch)

    /// Predefined macros hell:
    ///
    /// __GNUC__           Compiler is gcc, Clang or Intel on Linux
    /// __INTEL_COMPILER   Compiler is Intel
    /// _MSC_VER           Compiler is MSVC or Intel on Windows
    /// _WIN32             Building on Windows (any)
    /// _WIN64             Building on Windows 64 bit

    std::string compiler = "\nCompiled by ";

#ifdef __clang__
    compiler += "clang++ ";
    compiler += make_version_string(__clang_major__, __clang_minor__, __clang_patchlevel__);
#elif __INTEL_COMPILER
    compiler += "Intel compiler ";
    compiler += "(version ";
    compiler += stringify(__INTEL_COMPILER) " update " stringify(__INTEL_COMPILER_UPDATE);
    compiler += ")";
#elif _MSC_VER
    compiler += "MSVC ";
    compiler += "(version ";
    compiler += stringify(_MSC_FULL_VER) "." stringify(_MSC_BUILD);
    compiler += ")";
#elif __GNUC__
    compiler += "g++ (GNUC) ";
    compiler += make_version_string(__GNUC__, __GNUC_MINOR__, __GNUC_PATCHLEVEL__);
#else
    compiler += "Unknown compiler ";
    compiler += "(unknown version)";
#endif

#if defined(__APPLE__)
    compiler += " on Apple";
#elif defined(__CYGWIN__)
    compiler += " on Cygwin";
#elif defined(__MINGW64__)
    compiler += " on MinGW64";
#elif defined(__MINGW32__)
    compiler += " on MinGW32";
#elif defined(__ANDROID__)
    compiler += " on Android";
#elif defined(__linux__)
    compiler += " on Linux";
#elif defined(_WIN64)
    compiler += " on Microsoft Windows 64-bit";
#elif defined(_WIN32)
    compiler += " on Microsoft Windows 32-bit";
#else
    compiler += " on unknown system";
#endif

    compiler += "\nCompilation settings include: ";
    compiler += (Is64Bit ? " 64bit" : " 32bit");
#if defined(USE_VNNI)
    compiler += " VNNI";
#endif
#if defined(USE_AVX512)
    compiler += " AVX512";
#endif
    compiler += (HasPext ? " BMI2" : "");
#if defined(USE_AVX2)
    compiler += " AVX2";
#endif
#if defined(USE_SSE41)
    compiler += " SSE41";
#endif
#if defined(USE_SSSE3)
    compiler += " SSSE3";
#endif
#if defined(USE_SSE2)
    compiler += " SSE2";
#endif
    compiler += (HasPopCnt ? " POPCNT" : "");
#if defined(USE_MMX)
    compiler += " MMX";
#endif
#if defined(USE_NEON)
    compiler += " NEON";
#endif

#if !defined(NDEBUG)
    compiler += " DEBUG";
#endif

    compiler += "\n__VERSION__ macro expands to: ";
#ifdef __VERSION__
    compiler += __VERSION__;
#else
    compiler += "(undefined macro)";
#endif
    compiler += "\n";

    return compiler;
}


/// Debug functions used mainly to collect run-time statistics
static std::atomic<int64_t> hits[2], means[2];

void dbg_hit_on(bool b) noexcept
{
    ++hits[0]; if (b) ++hits[1];
}

void dbg_hit_on(bool c, bool b) noexcept
{
    if (c) dbg_hit_on(b);
}

void dbg_mean_of(int v) noexcept
{
    ++means[0]; means[1] += v;
}

void dbg_print()
{
    if (hits[0])
        cerr << "Total " << hits[0] << " Hits " << hits[1]
        << " hit rate (%) " << 100 * hits[1] / hits[0] << endl;

    if (means[0])
        cerr << "Total " << means[0] << " Mean "
        << (double)means[1] / means[0] << endl;
}


/// Used to serialize access to std::cout to avoid multiple threads writing at
/// the same time.

std::ostream &operator<<(std::ostream &os, SyncCout sc)
{
    static std::mutex m;

    if (sc == IO_LOCK)
        m.lock();

    if (sc == IO_UNLOCK)
        m.unlock();

    return os;
}


/// Trampoline helper to avoid moving Logger to misc.h
void start_logger(const std::string &fname)
{
    Logger::start(fname);
}


/// prefetch() preloads the given address in L1/L2 cache. This is a non-blocking
/// function that doesn't stall the CPU waiting for data to be loaded from memory,
/// which can be quite slow.
#ifdef NO_PREFETCH

void prefetch(void *)
{
}

#else

void prefetch(void *addr)
{
#  if defined(__INTEL_COMPILER)
    // This hack prevents prefetches from being optimized away by
    // Intel compiler. Both MSVC and gcc seem not be affected by this.
    __asm__("");
#  endif

#  if defined(__INTEL_COMPILER) || defined(_MSC_VER)
    _mm_prefetch((char *)addr, _MM_HINT_T0);
#  else
    __builtin_prefetch(addr);
#  endif
}

#ifndef PREFETCH_STRIDE
/* L1 cache line size */
#define L1_CACHE_SHIFT	7
#define L1_CACHE_BYTES	(1 << L1_CACHE_SHIFT)

#define PREFETCH_STRIDE (4 * L1_CACHE_BYTES)
#endif

void prefetch_range(void *addr, size_t len)
{
    char *cp = nullptr;
    const char *end = (char *)addr + len;

    for (cp = (char *)addr; cp < end; cp += PREFETCH_STRIDE)
        prefetch(cp);
}

#endif


/// std_aligned_alloc() is our wrapper for systems where the c++17 implementation
/// does not guarantee the availability of aligned_alloc(). Memory allocated with
/// std_aligned_alloc() must be freed with std_aligned_free().

void *std_aligned_alloc(size_t alignment, size_t size)
{
#if defined(POSIXALIGNEDALLOC)
    void *mem;
    return posix_memalign(&mem, alignment, size) ? nullptr : mem;
#elif defined(_WIN32)
    return _mm_malloc(size, alignment);
#else
    return std::aligned_alloc(alignment, size);
#endif
}

void std_aligned_free(void *ptr)
{
#if defined(POSIXALIGNEDALLOC)
    free(ptr);
#elif defined(_WIN32)
    _mm_free(ptr);
#else
    free(ptr);
#endif
}

#ifdef ALIGNED_LARGE_PAGES

/// aligned_large_pages_alloc() will return suitably aligned memory, if possible using large pages.

#if defined(_WIN32)

static void *aligned_large_pages_alloc_win(size_t allocSize)
{
    HANDLE hProcessToken{ };
    LUID luid{ };
    void *mem = nullptr;

    const size_t largePageSize = GetLargePageMinimum();
    if (!largePageSize)
        return nullptr;

    // We need SeLockMemoryPrivilege, so try to enable it for the process
    if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &hProcessToken))
        return nullptr;

    if (LookupPrivilegeValue(NULL, SE_LOCK_MEMORY_NAME, &luid)) {
        TOKEN_PRIVILEGES tp{ };
        TOKEN_PRIVILEGES prevTp{ };
        DWORD prevTpLen = 0;

        tp.PrivilegeCount = 1;
        tp.Privileges[0].Luid = luid;
        tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;

        // Try to enable SeLockMemoryPrivilege. Note that even if AdjustTokenPrivileges() succeeds,
        // we still need to query GetLastError() to ensure that the privileges were actually obtained.
        if (AdjustTokenPrivileges(
            hProcessToken, FALSE, &tp, sizeof(TOKEN_PRIVILEGES), &prevTp, &prevTpLen) &&
            GetLastError() == ERROR_SUCCESS) {
            // Round up size to full pages and allocate
            allocSize = (allocSize + largePageSize - 1) & ~size_t(largePageSize - 1);
            mem = VirtualAlloc(
                NULL, allocSize, MEM_RESERVE | MEM_COMMIT | MEM_LARGE_PAGES, PAGE_READWRITE);

            // Privilege no longer needed, restore previous state
            AdjustTokenPrivileges(hProcessToken, FALSE, &prevTp, 0, NULL, NULL);
        }
    }

    CloseHandle(hProcessToken);

    return mem;
}

void *aligned_large_pages_alloc(size_t allocSize)
{
    // Try to allocate large pages
    void *mem = aligned_large_pages_alloc_win(allocSize);

    // Fall back to regular, page aligned, allocation if necessary
    if (!mem)
        mem = VirtualAlloc(NULL, allocSize, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);

    return mem;
}

#else

void *aligned_large_pages_alloc(size_t allocSize)
{
#if defined(__linux__)
    constexpr size_t alignment = 2 * 1024 * 1024; // assumed 2MB page size
#else
    constexpr size_t alignment = 4096; // assumed small page size
#endif

  // round up to multiples of alignment
    size_t size = ((allocSize + alignment - 1) / alignment) * alignment;
    void *mem = std_aligned_alloc(alignment, size);
#if defined(MADV_HUGEPAGE)
    madvise(mem, size, MADV_HUGEPAGE);
#endif
    return mem;
}

#endif


/// aligned_large_pages_free() will free the previously allocated ttmem

#if defined(_WIN32)

void aligned_large_pages_free(void *mem)
{
    if (mem && !VirtualFree(mem, 0, MEM_RELEASE)) {
        DWORD err = GetLastError();
        std::cerr << "Failed to free transposition table. Error code: 0x" <<
            std::hex << err << std::dec << std::endl;
        exit(EXIT_FAILURE);
    }
}

#else

void aligned_large_pages_free(void *mem)
{
    std_aligned_free(mem);
}

#endif
#endif // ALIGNED_LARGE_PAGES

namespace WinProcGroup
{

#ifndef _WIN32

void bindThisThread(size_t)
{
}

#else

/// best_group() retrieves logical processor information using Windows specific
/// API and returns the best group id for the thread with index idx. Original
/// code from Texel by Peter Ã–sterlund.

int best_group(size_t idx)
{
    int threads = 0;
    int nodes = 0;
    int cores = 0;
    DWORD returnLength = 0;
    DWORD byteOffset = 0;

    // Early exit if the needed API is not available at runtime
    HMODULE k32 = GetModuleHandle(L"Kernel32.dll");
    if (k32 == nullptr)
        return -1;
    auto fun1 = (fun1_t)(void(*)())GetProcAddress(k32, "GetLogicalProcessorInformationEx");
    if (!fun1)
        return -1;

    // First call to get returnLength. We expect it to fail due to null buffer
    if (fun1(RelationAll, nullptr, &returnLength))
        return -1;

    // Once we know returnLength, allocate the buffer
    SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *buffer, *ptr;
    ptr = buffer = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *)malloc(returnLength);

    if (ptr == nullptr)
        return -1;

    // Second call, now we expect to succeed
    if (!fun1(RelationAll, buffer, &returnLength)) {
        free(buffer);
        return -1;
    }

    while (byteOffset < returnLength) {
        if (ptr->Relationship == RelationNumaNode)
            nodes++;

        else if (ptr->Relationship == RelationProcessorCore) {
            cores++;
            threads += (ptr->Processor.Flags == LTP_PC_SMT) ? 2 : 1;
        }

        assert(ptr->Size);
        byteOffset += ptr->Size;
        ptr = (SYSTEM_LOGICAL_PROCESSOR_INFORMATION_EX *)(((char *)ptr) + ptr->Size);
    }

    free(buffer);

    std::vector<int> groups;

    // Run as many threads as possible on the same node until core limit is
    // reached, then move on filling the next node.
    for (int n = 0; n < nodes; n++)
        for (int i = 0; i < cores / nodes; i++)
            groups.push_back(n);

    // In case a core has more than one logical processor (we assume 2) and we
    // have still threads to allocate, then spread them evenly across available
    // nodes.
    for (int t = 0; t < threads - cores; t++)
        groups.push_back(t % nodes);

    // If we still have more threads than the total number of logical processors
    // then return -1 and let the OS to decide what to do.
    return idx < groups.size() ? groups[idx] : -1;
}


/// bindThisThread() set the group affinity of the current thread

void bindThisThread(size_t idx)
{
    // Use only local variables to be thread-safe
    const int group = best_group(idx);

    if (group == -1)
        return;

    // Early exit if the needed API are not available at runtime
    HMODULE k32 = GetModuleHandle(L"Kernel32.dll");
    if (k32 == nullptr)
        return;
    auto fun2 = (fun2_t)(void(*)())GetProcAddress(k32, "GetNumaNodeProcessorMaskEx");
    auto fun3 = (fun3_t)(void(*)())GetProcAddress(k32, "SetThreadGroupAffinity");

    if (!fun2 || !fun3)
        return;

    GROUP_AFFINITY affinity;
    if (fun2((USHORT)group, &affinity))
        fun3(GetCurrentThread(), &affinity, nullptr);
}

#endif

} // namespace WinProcGroup

#ifdef _WIN32
#include <direct.h>
#define GETCWD _getcwd
#else
#include <unistd.h>
#define GETCWD getcwd
#endif

namespace CommandLine
{

string argv0;            // path+name of the executable binary, as given by argv[0]
string binaryDirectory;  // path of the executable directory
string workingDirectory; // path of the working directory

void init(int argc, const char *argv[])
{
    (void)argc;
    string pathSeparator;

    // extract the path+name of the executable binary
    argv0 = argv[0];

#ifdef _WIN32
    pathSeparator = "\\";
#ifdef _MSC_VER
    // Under windows argv[0] may not have the extension. Also _get_pgmptr() had
    // issues in some windows 10 versions, so check returned values carefully.
    char *pgmptr = nullptr;
    if (!_get_pgmptr(&pgmptr) && pgmptr != nullptr && *pgmptr)
        argv0 = pgmptr;
#endif
#else
    pathSeparator = "/";
#endif

    // extract the working directory
    workingDirectory = "";
    char buff[40000];
    const char *cwd = GETCWD(buff, 40000);
    if (cwd)
        workingDirectory = cwd;

    // extract the binary directory path from argv0
    binaryDirectory = argv0;
    const size_t pos = binaryDirectory.find_last_of("\\/");
    if (pos == std::string::npos)
        binaryDirectory = "." + pathSeparator;
    else
        binaryDirectory.resize(pos + 1);

    // pattern replacement: "./" at the start of path is replaced by the working directory
    if (binaryDirectory.find("." + pathSeparator) == 0)
        binaryDirectory.replace(0, 1, workingDirectory);
}


} // namespace CommandLine
